1. Field of the Invention
The present invention relates to steering assist devices for vehicles, and more particularly to steering assist devices that prevent a running vehicle from deviating from its lane.
2. Description of the Related Art
If a vehicle deviates from its lane on a highway etc. due to driver's carelessness or a road surface condition, there is a risk that the vehicle may contact other vehicle(s) or a guardrail. As a solution, lane departure warning systems are developed which obtain road surface information and relative position information between the vehicle and its lane based on an image shot by a camera mounted on the vehicle and warn the driver when the vehicle is about to deviate from its lane. See, e.g., Japanese Patent Application Publication No. 2013-212839 (JP 2013-212839 A), Japanese Patent No. 4292562 (JP 4292562 B), and Japanese Patent Application Publication No. H11-34774 (JP H11-34774 A).